This invention relates generally to copier apparatus, and, more particularly, to a roll fusing system for fixing electroscopic toner material to a support member.
In the process of xerography, a light image of an original to be copied is typically recorded in the form of a latent electrostatic image upon a photosensitive member with subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual image can be either fixed directly upon the photosensitive member or transferred from the member to a sheet of plain paper with subsequent affixing of the image thereto.
There are various ways of fusing or affixing the toner particles to the support member, one of which is by the employment of heat. In order to permanently affix or fuse electroscopic toner material onto a support member by heat, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This action causes the toner to be absorbed to some extent into the fibers of the support member which, in many instances, constitute plain paper. Thereafter, as the toner material cools, solidification of the toner material occurs causing the toner material to be firmly bonded to the support member. In both the xerographic as well as the electrographic recording arts, the use of thermo energy for fixing toner images onto a support member is old and well know.
One approach to thermofusing of electroscopic toner images onto a support has been to pass the support with the toner images thereon between a pair of opposed roller members, at least one of which is either externally or internally heated. During operation of a fusing system of this type, the support member to which the toner images are electrostatically adhered is moved through the nip formed between the rolls with the toner images contacting the fuser roll to thereby effect heating of the toner images within the nip.
In order to perform maintenance of repairs on a roll fuser system it is desirable to be able to remove the backup roll from the fuser roll system. If conventional fasteners are employed for securing the backup roll in place, excessive handling of the roll is required. This can present a problem, particularly when the backup roll is hot.
Accordingly, the principal object of this invention is to provide a new and improved copying apparatus.
It is a more particular object of this invention to provide a new and improved roll fusing apparatus for utilization in an electrostatic copier apparatus.
Another object of this invention is to provide a roll fusing apparatus which utilizes substantially fewer components than known roll fuser apparatus and which is therefore less costly to manufacture as well as maintain.
Yet another object of this invention is to provide new and improved structure for permitting removal of a backup roll from a roll fuser assembly with a minimum of handling.